Find random corruptions

mdata/cache/ccache_metric_test.go

@@ -3,8 +3,10 @@ package cache
 import (
 	"errors"
 	"fmt"
+	"math/rand"
 	"sort"
 	"testing"
+	"time"
 
 	"github.com/grafana/metrictank/mdata/cache/accnt"
 	"github.com/grafana/metrictank/mdata/chunk"
@@ -203,6 +205,73 @@ func TestCorruptionCase1(t *testing.T) {
 	})
 }
 
+func getRandomNumber(min, max int) int {
+	return rand.Intn(max-min) + min
+}
+
+// getRandomRange returns a range start-end so that
+// end >= start and both numbers drawn from [min, max)
+func getRandomRange(min, max int) (int, int) {
+	start := getRandomNumber(min, max)
+	end := getRandomNumber(start, max)
+	return start, end
+}
+
+func TestCorruptionCase2(t *testing.T) {
+	rand.Seed(time.Now().Unix())
+	_, ccm := getCCM()
+	iterations := 100000
+
+	// 100 chunks, first t0=t10, last is t0=1000
+	chunks := generateChunks(t, 10, 100, 10)
+
+	var opAdd, opAddRange, opDel, opDelRange int
+	var adds, dels int
+
+	for i := 0; i < iterations; i++ {
+		// 0 = Add
+		// 1 = AddRange
+		// 2 = Del
+		// 2 = Del range (via multi del cals)
+		action := getRandomNumber(0, 4)
+		switch action {
+		case 0:
+			chunk := getRandomNumber(0, 100)
+			t.Logf("adding chunk %d", chunk)
+			ccm.Add(0, chunks[chunk])
+			opAdd++
+			adds++
+		case 1:
+			from, to := getRandomRange(0, 100)
+			t.Logf("adding range %d-%d", from, to)
+			ccm.AddRange(0, chunks[from:to])
+			adds += (to - from)
+			opAddRange++
+		case 2:
+			chunk := getRandomNumber(0, 100)
+			t.Logf("deleting chunk %d", chunk)
+			ccm.Del(chunks[chunk].Ts) // note: chunk may not exist
+			opDel++
+			dels++
+		case 3:
+			from, to := getRandomRange(0, 100)
+			for chunk := from; chunk < to; chunk++ {
+				t.Logf("deleting chunk %d", chunk)
+				ccm.Del(chunks[chunk].Ts) // note: chunk may not exist
+			}
+			opDelRange++
+			dels += (to - from)
+		}
+
+		if err := verifyCcm(ccm); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	fmt.Printf("operations: add %d - addRange %d - del %d - delRange %d\n", opAdd, opAddRange, opDel, opDelRange)
+	fmt.Printf("total chunk adds %d - total chunk deletes %d\n", adds, dels)
+}
+
 // verifyCcm verifies the integrity of a CCacheMetric
 // it assumes that all itergens are span-aware
 func verifyCcm(ccm *CCacheMetric) error {